Toxic Phenols in Farmland Soils of Yenagoa Communities: Concentrations and Risk Assessment

Abstract

: Phenolic compounds are potentially toxic contaminants that may accumulate in agricultural soils and pose risks to soil organisms and terrestrial ecosystems. This study investigated the concentrations, distribution, and potential ecological risks of eleven priority phenolic compounds in farmland soils from Kpansia (KP), Ikarama (IK), and Amarata (AM) communities in Yenagoa Local Government Area, Bayelsa State, Nigeria. A total of 135 individual soil samples collected at 0–20 cm depth were composited into 27 samples and analyzed for phenol (Ph), 2-chlorophenol (2-CP), 2-nitrophenol (2-NP), 2,4-dimethylphenol (2,4-DMP), 2,4-dichlorophenol (2,4-DCP), 4-chloro-3-methylphenol (4-C-3-MP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,4-dinitrophenol (2,4-DNP), 4-nitrophenol (4-NP), 2-methyl-4,6-dinitrophenol (2-M-4,6-DNP), and pentachlorophenol (PCP) using gas chromatography–mass spectrometry. All eleven compounds were detected, with individual concentrations ranging from 0.08 to 1.46 mg/kg and total phenolic concentrations ranging from 4.70 to 10.34 mg/kg. Mean total concentrations were 7.19 ± 3.76 mg/kg in IK, 6.22 ± 2.87 mg/kg in KP, and 5.73 ± 2.07 mg/kg in AM. PCP had the highest overall contribution (15.7%), followed by 2,4-DMP (13.6%) and 2-M-4,6-DNP (12.1%). Ecological risk assessment based on risk quotients (RQ = MEC/PNEC) showed that all compounds except 4-NP had mean RQ values >1. PCP recorded the highest mean RQ (334.49), while cumulative ∑11RQ values were 883.42, 756.36, and 460.78 for KP, IK, and AM, respectively. The findings indicate multiple phenolic contamination and substantial screening-level potential ecological risks, highlighting the need for continued monitoring, source identification, pollution control, and sustainable management of agricultural soils in Yenagoa LGA.